1. Field of the Invention
This invention relates to a communication apparatus having an antenna and wireless communication functions, such as a portable headphone, or a portable headset.
2. Description of the Related Art
In recent years, developments have been made particularly in various portable communication apparatuses having close-range wireless communication functions. Products called headphones or headsets have been developed as portable communication apparatuses. Here, headphones mainly correspond to a portable audio device having an audio speaker which reproduces music data. Meanwhile, the headset has a function for conversation or data communication and has both a speaker and microphone and is utilized, for example, in connection with a cellular telephone.
Japanese Patent Application Publication (KOKAI) No. 9-270729 discloses a headset-type communication device having a satellite communication cellular telephone function. This device has a structure in which a pair of ear pad parts (earmuffs) including speakers are connected to each other by a headband, and an antenna is attached to one of the ear pad parts. In this device, a rod-like antenna is provided in the form of a protrusion from one ear pad part. When using this device as a bi-directional communication apparatus, the device may be provided with a microphone arm.
Japanese Patent Application Publication (KOKAI) No. 2002-112383 discloses a headphone-type communication device having a function of digital transmission/reception to/from an audio player, and reproduces music data transmitted from the audio player.
When a user wears the headset/headphone communication device as described above on the head, the communication device is used with its antenna situated along the temporal region of the head. Therefore, the temporal region of the head may block out electric waves from a satellite functioning as a source which sends data, depending on the orientation of the user relative to the signal source. The gain of the antenna hence decreases. To avoid this problem, the portable wireless terminal is constructed in a structure comprising a terminal body, an antenna support tool attached to the head of the user who uses the portable wireless terminal, and an antenna supported on the head of the user by the antenna support tool and connected to the terminal body by an antenna cable. In this way, the antenna is positioned above the head of the user, so that communication is enabled without concern about the situation of use of the portable terminal or the direction thereof.
However, since the antenna is provided in the side of only one of the ear pad parts, the head of the user may still shut out electric waves. This leads to a great decrease in antenna gain, depending on the positional relationship with devices as a target of communication. Further, the form of the antenna protruding from the ear pad part is not practical, from the aspects of safety and design.